Laser-Patterned Oxidized Steel Mesh with Dual Wettability for Efficient Atmospheric Water Harvesting

Surface modification techniques play a vital role in improving fogwater harvesting efficiency. In this study, stainless steel mesh was modified using pulsed laser ablation and subsequently functionalized with stearyl alcohol, an eco-friendly, low cost and fluorine-free hydrophobic agent. The fabricated surfaces were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), and elemental mapping to confirm their morphological and chemical features. The effects of laser patterning (0.5 and 1 cm line intervals), stearyl alcohol concentration, and immersion time were systematically investigated. Among all prepared samples, the chemically modified mesh with 0.5 cm laser patterning (m-L5) exhibited the highest performance, achieving a water harvesting rate (WHR) of 7.36 mg min^-1 cm^-2, which is ∼2.5 times higher than the pristine stainless-steel mesh. Furthermore, tilting angle experiments revealed that horizontal positioning (0°) provides superior efficiency compared to 45° and 90°. These results highlight the potential of sustainable surface engineering strategies for effective fog collection.